LED照明系统具有效率高、寿命长等优点，对实现节能减排和缓解环境污染有重要意义。但目前LED照明产品的寿命和可靠性不尽满意，LED照明产品经常在标称寿命前失效，无法高可靠运行，增加能源损耗和运行成本。本项目将针对此问题，系统研究影响LED芯片、驱动器电容和功率开关等关键器件寿命和可靠性的因素，建立器件级寿命和可靠性模型，提出多物理场耦合的LED结温预测方法；研究热耦合对LED光源、驱动器寿命和可靠性的影响，提出基于热耦合作用的改进型热网络模型，从而建立拓扑级寿命和可靠性模型；研究不同时间尺度下的系统光-电-热模型，建立不同时间尺度的系统级寿命和可靠性模型；提出变化工况下寿命和可靠性预测方法。通过以上研究准确预测出不同应用场合、不同运行工况下的LED照明系统真实的寿命和可靠性，并提出有效的电流控制方案和热管理方案来提高其寿命和可靠性，从而真正实现高效率、长寿命、高可靠运行的LED照明系统。

With the advantages of high efficiency and long lifetime, the Light-Emitting Diode (LED) lighting is profitable to save the energy consumption and mitigate the environmental pollution. However, the customer experiences may be different and some of the LED lamps can fail in a considerable time ahead of the claimed life, which increases the running and maintenance costs. To solve it, this project will firstly analyze the key parameters which may degrade LED chips, capacitors and switching components and so on. Then the component-level models of lifetime and reliability will be proposed to predict the lifetime and reliability of those key components. The multi-physics field based analysis is proposed to predict the LED junction temperature accurately. Due to the effect of the thermal coupling to temperature distribution, an improved thermal model will be analyzed to facilitate the topology-level models for lifetime and reliability. Because the lifetime of the whole LED lighting system is affected by many parameters with different time scales, the multiple time scale models for the LED lighting system are proposed to estimate the system-level lifetime and reliability. The LED lighting systems usually work in the different locations and variable environmental conditions, and an accurate lifetime prediction method will be proposed to estimate the real lifetime and reliability information of the LED lighting system in field operation. With these models and information, the current driving schemes and thermal control solutions will be proposed to improve the lifetime and reliability of the whole LED lighting system. All above technologies will make the whole LED lighting system more efficient, durable and reliable and guarantee the energy saving of LED lighting system.